Surface pretreatment of fabrics for laser writer applications

ABSTRACT

Pretreatment of a fabric using a material that binds to the fabric and changes some characteristic of the fabric. In an embodiment, the characteristic that is changed can be at least one of stain and flash for wrinkle resistance. The material can be Permafresh material. The material can bind to the fabric, and intends to be maintained within the fabric for the life of the fabric. After pretreatment, the pretreated material is processed by a laser which intends to change the look of the material without undesirably damaging the material. The treatment may make the treatment by lasers more consistent and allow the lazed graphic to maintain its quality after repeated washings and wearing.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from provisional application No.60/628,311, filed Nov. 15, 2004, and 60/662,469, filed Mar. 30, 2005,the contents of both of which are herewith incorporated by reference.

BACKGROUND

Technolines LLC has been granted a number of patents, including U.S.Pat. No. 5,990,444 and others, which describe lasers being used to writegraphic images and patterns on substrates. The lasers may write graphicimages on fabric substrates such as cotton, polyester, suede, leather,and the like. The laser should write with an output power or energy“density” per unit time, or EDPUT, that makes a mark on the fabric,without undesirable damage to the fabric.

SUMMARY

The present application describes a technique of treating fabrics priorto and/or after marking them with a laser. The treatment allows thelaser to make a better sustainable mark on the fabric (specificallyafter repeated washes or wear).

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 show embodiments of the system with a pretreatment, andlaser marking part.

DETAILED DESCRIPTION

The general structure and techniques, and more specific embodimentswhich can be used to effect different ways of carrying out the moregeneral goals are described herein.

A basic embodiment is shown in FIG. 1. FIG. 1 shows the operation alonga conveyor 100, however, it should be understood that the operation canbe carried out in one place, or as part of any other kind ofworkstation. A workpiece, e.g., a fabric item, or clothing part, shownas 99, is exposed to the output of a laser 105. A controller 110controls the laser. The controller may be internal to the laser 105 ormay be completely separate. The controller causes the laser to output abeam which has an energy amount that causes a change to the look of thefabric. The energy amount may be set as an energy density per unit time,which may avoid undesirable damage to the fabric and may alter thefabric chemistry. The controller, for example, may be a computer that iscontrolled according to a prestored program. The program may include animage of a design to be scribed. The design may be image portionsrepresenting words, or may be image portions representing an actualimage, such as a logo. The computers described herein may be any kind ofcomputer, either general purpose, or some specific purpose computer suchas a workstation. The computer may be a Pentium class computer, runningWindows XP or Linux, or may be a Macintosh computer. The programs may bewritten in C, or Java, or any other programming language. The programsmay be resident on a storage medium, e.g., magnetic or optical, e.g. thecomputer hard drive, a removable disk or other removable medium. Theprograms may also be run over a network. FIG. 2 illustrates theincorporation of the invention in a typical screen printing carouseloperation. For those skilled in the art, it is apparent that thetraditional multiple arms which apply different colored paints to thefabric via individual screen printing, can be situated anywhere alongthe carousel shown in FIG. 2.

It has been observed that most textile substrates are very responsive tothe laser writing process. After the textile is processed by the laser,it is desirable that the image that was written during the operationshould be seen immediately, and that the image is also seen later—e.g.,after wearing or washing. However, on certain garments, and specificallyon some cotton materials, the graphic has been observed to disappear orreduce in contrast after washing. The kinds of materials, and thereasons why this happens are unknown. The materials and results have notbeen easily susceptible of prediction.

For example, this problem could exist on one specific dyed cottonmaterial. However, the problem might not exist on a similar dyed cottonmaterial of the same color. Some colors tend to produce betterlaser-scribed graphics than others. There has been minimal consistencybetween the processes. For example, scribed graphics on blue and redcottons have tended to look better after washing then the same graphicslazed on black or pink cottons.

It is postulated that variations in the yarn, weaving, dyes, retentiontechniques or other material variation might be responsible for theinconsistent problem. However, this problem prevented laser scribedgraphics from being used on all dyed fabrics; while also withstandingrepeated washing.

The inventor believed that there must be some spray or surface treatmentwhich could change the characteristics of the material, here cotton, toallow the scribed graphics to withstand repeated washings. A variety ofdifferent surface treatments were investigated. A specific productcalled PermaFresh was found from a chemical company called Omnova. ThePermaFresh product is a total fabric treatment for stain and wrinkleresistance. This treatment is meant to remain bound to the fabric forthe life of the fabric, and to withstand washing.

Permafresh surprisingly proved to essentially eliminate the post washcharacteristic problem when processing laser scribed graphics on manydifferent dyed materials and colors. Other analogous materials may alsobe used, which will have similar results.

The PermaFresh compound is applied, and heat cured, to alter the surfacechemistry of the material in some way. Element 120 illustrates thefabric pretreatment process, where the sprayer 120 sprays the material125 on to the workpiece 99 prior to laser scribing. The heat curing maybe a totally separate step along the conveyor, or may rely on the heatproduced by the laser 105 itself. This allows the laser-written graphicsto appear crisp and clean even after repeated washings. This also madeit possible, and also facilitates the laser writing of the graphics oncertain cotton colors such as black and pink. Laser writing on black andpink has historically been difficult or impossible prior to thispretreatment technique.

A post treatment step 130 applies a post treatment material on to theworkpiece. The post treatment may simply be for example from the heatflow, or may be either another wrinkle resistance material or the samewrinkle resistance material. Heat may serve to further fix the wrinkleresistant material in place. Typically the heat application is appliedafter the spaying operation and before the lazing operation. Anadditional post treatment as in step 180 in FIG. 2 could actually coolthe spayed and heated material.

The conveyor may also include a washing station shown as 140. Washingstation 140 may apply soap, using brushes as shown, and may vacuum awaythe soap residue, and/or may also provide a rinse operation to thematerial after the soap has been applied or may only provide a rinsefunction. Alternatively, a more conventional washing machine can beused, instead of doing this along the conveyor. The washing operationwould be carried out after all laser marking and heating steps arecomplete.

While PermaFresh has been described as the one pretreatment material, itshould be understood that any treatment process that remains bound tothe fabric for the life of the garment may be able to be similarly used.More specifically, any such treatment product which provides stainand/or wrinkle resistance and/or other kind of treatment to the materialwhich changes the characteristic of the material, may be used. It may bepostulated that the stain protection somehow chemically alters thesurface to allow it to retain the laser formed image after washing. Thepretreatment that is used should preferably be liquid, it shouldpreferably remain bound to the fabric for either the life of the fabricor at least for a number of washing cycles of the fabric, and it shouldat least in one embodiment, have the function of at least one of wrinkleand/or stain resistance.

Although only a few embodiments have been disclosed in detail above,other embodiments are possible and the inventor (s) intend these to beencompassed within this specification. The specification describesspecific examples to accomplish a more general goal that may beaccomplished in another way. This disclosure is intended to beexemplary, and the claims are intended to cover any modification oralternative which might be predictable to a person having ordinary skillin the art. For example, other materials, that is, other than Permafreshmay be used. An important part of the material is that it alters thecharacteristic of the fabric, and in a specific way. The fabric'scharacteristic should be altered in a way that makes it more resistant.Wrinkle resistance and stain resistance are two exemplary ways in whichthe characteristic should be altered.

Also, the inventor(s) intend that only those claims which use the words“means for” are intended to be interpreted under 35 USC 112, sixthparagraph. Moreover, no limitations from the specification are intendedto be read into any claims, unless those limitations are expresslyincluded in the claims.

1. A method, comprising: treating a fabric material with a treatmentthat remains bound to the fabric and is intended to change somecharacteristic of the fabric to make the fabric more resistant; andusing a laser to form a perceivable change to a color of the fabricwithout undesirably damaging the fabric.
 2. A method as in claim 1,wherein said treatment is a liquid treatment that prevents at least oneof stain and/or wrinkle resistance.
 3. A method as in claim 1, whereinsaid treatment is Permafresh pretreatment spray.
 4. A method as in claim2, further comprising heat curing the liquid treatment on the fabric. 5.A method as in claim 1, wherein said using the laser comprises producinga laser output that produces an energy density per unit time thatchanges a look of the fabric without undesirably damaging the fabric. 6.A method as in claim 1, wherein said fabric is one of a black coloredfabric or a pink colored fabric.
 7. A method, comprising: spraying apretreatment on a fabric, said pretreatment being of a type which isintended to withstand repeated washings, and which pretreatment isintended to change a characteristic of the fabric to make the fabricmore resistant; after said pretreating, heating said fabric, and using alaser to apply energy to a surface of said fabric, in only a pluralityof discrete locations, which plurality of discrete locations define adesired graphic to be seen on said fabric.
 8. A method as in claim 7,wherein said pretreatment is a pretreatment that is intended to providewrinkle resistance for the life of the fabric.
 9. A method as in claim7, wherein said pretreatment is a material that is intended to providestain resistance for a life of the fabric.
 10. A method as in claim 7,wherein the fabric is one of pink or black in color.
 11. A method as inclaim 7, further comprising post treating the material, after said usinga laser.
 12. A method as in claim 7, further comprising washing thematerial, after said using the laser.
 13. A method as in claim 7,wherein said pretreatment uses Permafresh spray material.
 14. A methodas in claim 7, wherein said spraying, said heating and said using alaser, are all carried out along a conveyor.
 15. A system, comprising: afirst part which applies a liquid based fabric pretreatment material toa fabric, said fabric pretreatment material being a material that bindsto the fabric to withstand washing, and which alters a characteristic ofthe fabric to make the fabric more resistant; and a laser part, whichprovides an output laser to selected locations based on a desiredgraphic, said laser output being of a power that produces a change tothe material without undesirably damaging the material, and of a powerthat changes a look of the material.
 16. A system as in claim 15,further comprising a conveyor, having a surface intended to carry thefabric material, and wherein said first part and said laser part arelocated along the conveyor, with the laser part being downstream of thefirst part.
 17. A system as in claim 16, further comprising a posttreatment part, also along said conveyor, which treats the materialafter processing by the laser.
 18. A system as in claim 16, furthercomprising a washing machine part, which carries out the function of awashing machine along the conveyor, downstream of said laser.
 19. Asystem as in claim 15, wherein said pretreatment material is PermaFresh,which forms a stain and wrinkle resistance to the material.
 20. A systemas in claim 15, further comprising a second part which applies heat tothe pretreated part. 21-22. (canceled)